Andy13186

What would be needed for a 2011 GT to handle better than a stock 2012 boss 302 and the laguna seca?

I currently just have koni sport dampers steeda sport springs and forgestar f14 rims (19x9 and 20x10.5) with 255/40/19 michelin pilot super sport tires on the front, 295 30 20's on the rear.

Do sway bars and LCA's etc make a significant difference in actual handling? or would turning my dampers to have a stiffer rebound setting have more of an effect?

jayman33

When you say handle, what exactly do you mean? Handling is very vague, street, strip, road course, etc, etc. The 19 in the front and 20 in the rear for rims doesn't necessarily aid in handling. Mess with what you have now, its not bad. Do you have CC plates to mess with camber? What brakes do you have? That can influence your handling as well.

Rolling13

Looks like you are in pretty good shape. Sway bars will help even more.

Andy13186

I have camber bolts (no cc plates) and the camber is set to about ~ -1.8. I have stock 2011 gt brakes. I also have roush axlebacks which give about 20 lbs of weight reduction in the rear.

Havent had many issues with the brakes and i dont do road courses, mainly just spirited driving on some of the good streets around here.

So far i would say the tires made the biggest difference in actual cornering grip.. with just the rims and tires i could take turns much faster and get on the throttle way earlier. Now that its getting cooler here in florida (60's) i can spin them easier than i expected though.. I have 3.31's and can go full throttle in 2nd gear at 30 mph and spin them for like 40 feet, which i didnt expect to be able to do.

Norm Peterson

At this stage, what you're asking for is to potentially outhandle the Boss. Emphasis on "potentially".

From the list you have there . . . I'd start with a lot less tire size stagger and wheel widths that are much closer to being the same. Holding everything else the same, you've added some understeer by unbalancing the wheel:tire setup toward potentially greater additional rear grip and lower rear slip angles.

I'm afraid that "hard street driving" is kind of vague - for some people intentionally getting to and cornering at half a lateral g is a lot, and that's barely out of the range where tire behavior can generally be considered 'linear'.

Swapping springs, sta-bars and end settings, shocks, alignment settings, etc., are all considerations for getting to "better handling", but not answers in and of themselves. To get really at that "better handling" you have to tune them to work together and with you and the way you tend to drive. I'm guessing that you will have to learn to drive a little differently as well, since most people learn that they can get away with a lot of nonsense down under 0.3 lat-g that would put them off the black part at 9/10ths.

Tuning the bars will make a difference that you may feel (I can't guarantee this), but you should easily feel a difference in LCAs with either firmer bushings or shericals (in any combination). With at least one end some sort of spherical (sphericals are preferred for corner-carving), you'll mostly feel the power hit the tires a little quicker and the new LCAs won't add much roll stiffness to the rear suspension (which you don't want them doing anyway).


Norm

Andy13186

I thought stagger would actually be beneficial since it will enable you to get on the throttle alot earlier than you would have been able to with non staggaered tires. I havent experienced any understeer, especially if i brake before entering the corner and just control it through the corner with the gas.

Also most of the best handling cars do have staggered tires

Boss 302 has 255's front 285's rear

z06's have 275's and 325's

Porsche 911 gt3's have 235's and 315's


Ferrari 599 GTO 285's and 305's

Mabe ill get 265's for the front next time i need fronts

tj@steeda

Andy,

we actually talked about this last year and Gus is your man to talk to when it comes to making your GT handle like a Boss ... it can be done. I have driven the Steeda Street Fighter and that car will out handle a lot of cars on the street.

Here is the video that MM&FF did with a 2011 GT. You can see what this kind of package can do to a stock Mustang.

http://www.steedablog.com/2011/10/mm...ck-with-a-5-0/

PM if you would like me to get your information and either have Gus or Matt contact you?

Best Regards,

TJ

Norm Peterson

I think you need a clearer idea of what understeer really is and what it means. Then it might be easier to see that staggered sizes do not cause "good handling", only that they're a tuning tool for making any given chassis behave as intended. And that since all cars are far from being "equal", the same tricks with stagger are not applicable to all cars if improved handling is truly the goal.

Briefly, for light understeer you want the front tire slip angles to be only a little higher than the rear tire slip angles.

The "understeer" that you feel when you drive any car is the net result of several effects that individually affect the front and rear slip angles. Aside from tire width (properly supported), things like weight distribution and the camber that the tires actually operate at are among the more important.

So an intelligent approach tends to put the wider/larger tires where the greater weight is (that being at the rear of the Ferrari and Porsche). It also rewards SLA front suspension geometry as being geometrically superior to a strut suspension by permitting a slightly narrower tire to perform appropriately (I'm mainly thinking 'Corvette' here, but this also applies to the Ferrari).

The S197 Mustang really occupies a different place in the car spectrum, being a good bit less expensive than any of your other examples. It is safe to assume that a wider range of driver behavior/experience/skill/etc. will exist among Mustang buyers than among those who can afford any of those others (at over double the price). So you have to dial the suspension tuning a bit more conservatively. To this same end, Porsche has been whittling away at the basic problems of the 911's basic arrangement for about 50 years. You're either going to get pretty good at designing band-aids or you'd have given up on the configuration.

There is a separate reason entirely, and that has more to do with things like corporate handling standards. What this means is that the vehicles as produced and offered for sale are occasionally (perhaps more frequently than we realize) tuned to have greater understeer at the limit even on the cars for which very hard cornering is envisioned. One of the easier ways to accomplish this is with narrower tires up front, never mind that the visual appearance doesn't exactly hurt sales among the majority of buyers.

Specifically, Mustangs suffer from less-than-optimum strut geometry up front, coupled with 55% of the car weight also being up there. If near-the-limit handling is what you're really after, the last thing you want to be doing here is throwing away front grip.

The cars that you want to be comparing to are the Mustangs and perhaps the 3rd and 4th generation Camaros and Firebirds - as configured for autocross. Mostly, that's a 2nd gear activity at speeds comparable to what you see in normal driving. Meaning that even without a power adder you've got way more power on tap than you can put down any old time you want to and that you're accustomed to have driven that fast at least along more or less straight stretches of road. You'll find that the top drivers in this activity all run a "square" setup at least as far as the tire size is concerned.

Check Sam Strano's results and what he ran during any of his Mustang or Camaro years, or Terry and Amy Fair's results at this past Solo Nationals (Terry managed 4th in ESP in an overweight daily-driven fully-streetable-in-Texas-summers car against dedicated stripped, lightened, and trailered competition). What you WON'T find in the setups of those folks' cars is any tire stagger.


Norm

Norm Peterson

Two thoughts here specifically.

One is that any ability to get into the throttle sooner is not a freebie. With greater understeer and at the limit, your cornering speed will be slower and your turn-in less precise (due to those needlessly large front slip angles compared to the rear ones). In addition, you run the risk of power-on understeer if your acceleration lifts enough load off the front tires - never mind the understeer effect coming from your limited slip diff under power. Being able to get into the throttle sooner isn't all the help it sounds like if you still can't get into it enough harder without running out of road on track out.

The second is that it is possible to tune around a staggered tire setup to some extent. But the end result is not as stable because you're doing it not just to permit feeding greater power to the rear wheels, you're demanding that you do so (and do so with a more precise amount of throttle).


It's there, you're just not driving hard enough for it to be noticeable to you, and just because you may be controlling the understeer/oversteer balance with the throttle doesn't mean that the car itself is neutral.

Street driving is like that, very few people actually drive as hard relative to their cars' capabilities as they think they're doing. At least subconsciously you're leaving a lot on the table - things like trees, utility poles, and ditches tend to hurt should you directly encounter any of them - so you maintain more margin than you think. IOW, if you could literally rip one of your favorite corners up out of the ground and paste it intact down onto a real race track with plenty of unobstructed runoff room, your corner entry the way you drive it now would be too slow. Please don't try to verify this on the roads the way they are, just take my word for it.


I suppose if anything, staggered tire sizes can feel more comfortable to most drivers because it doesn't feel like the tail is gonna come around on you unless you do something kinda stupid. Maybe that's good enough for lots of folks . . .


Norm

Andy13186

Thanks for the posts norm, good read there.


Another car, the 2013 gt500s have 265's front 285 rear , slightly less stagger than the boss,, it also probably has a few hundred more pounds of weight over the front than the boss's or GT's due to the SC setup.